1. Field of the Invention
The present invention relates to a method of fabricating a wavelength division multiplexed (WDM) unit, and more particularly to a method of fabricating a WDM unit with less reflection loss and insertion loss.
2. Description of Related Art
With reference to FIG. 12, a conventional method of producing a WDM unit is disclosed in U.S. Pat. No. 6,185,347.
According to the conventional method, a dual fiber pigtail (135) is inserted into a second holding tube (glass tube 130) to construct a first optical collimator with a WDM filter (105) by applying a heat curing epoxy (115) between the dual fiber pigtail (135) and heat curing epoxy (115). A single fiber pigtail (175) is inserted into a third holding tube (glass tube 165) to construct a second optical collimator. Lastly, the two optical collimators are aligned and sealed together. However, the procedures for adjusting and aligning the first and second optical collimators are time-consuming and troublesome.
Additionally, the WDM filter (105) attached to the first optical collimator is easily tilted, because the heat curing epoxy (115) for sticking the WDM filter (105) on the GRIN lens (110) shrinks/expands during temperature variations. The tilted WDM filter (105) causes the WDM unit to raise the reflection loss and insertion loss.
In order to obviate and/or alleviate the problem of the conventional method for producing a WDM unit, the present invention provides an improved method for fabricating a WDM unit having accurate alignment with timesaving procedures.